Purine Flashcards
What is the structure of DNA?
DNA is a double-stranded molecule found in the nucleus of eukaryotic cells and the cytoplasm of prokaryotic cells.
What are the components of DNA?
Nucleotides, nitrogenous bases, and phosphate group.
What are the building blocks of DNA?
Nucleotides.
What are the components of a nucleotide?
Phosphate group, sugar (deoxyribose), and nitrogenous base.
Name the purines found in DNA.
- Adenine (A) * Guanine (G)
Name the pyrimidines found in DNA.
- Cytosine (C) * Thymine (T) * Uracil (U)
What is the base pairing rule in DNA?
A pairs with T, and C pairs with G.
What is the difference between a nucleotide and a nucleoside?
Nucleotide: Base + Sugar + Phosphate group; Nucleoside: Base + Sugar (no phosphate group).
What is DNA methylation?
Addition of a methyl group to cytosine bases, often in CG-rich regions (CpG islands).
What is the effect of DNA methylation on gene transcription?
It inhibits gene transcription.
What is the significance of DNA methylation in epigenetics?
It plays a role in gene regulation.
Is DNA methylation common in bacteria?
Less common; it helps protect against viral infection.
What is chromatin?
Complex of DNA and proteins.
What are histones?
Proteins that help package DNA into nucleosomes.
What are nucleosomes?
Basic units of chromatin, consisting of DNA wrapped around a core of histone proteins.
What is heterochromatin?
Tightly packed chromatin, transcriptionally inactive.
What is euchromatin?
Loosely packed chromatin, transcriptionally active.
What is acetylation in the context of histone modifications?
Addition of acetyl groups to lysine residues on histones, leading to chromatin relaxation and increased transcription.
What is deacetylation?
Removal of acetyl groups, leading to chromatin condensation and decreased transcription.
What is drug-induced lupus related to histones?
Autoantibodies against histones.
What are histone deacetylase inhibitors?
Potential therapeutic agents for cancer and Huntington’s disease.
Fill in the blank: DNA is a ________ molecule.
double-stranded
True or False: Euchromatin is transcriptionally inactive.
False
